Systems employing computers often provide one or more clock sources that can be used as a system clock to drive the processor, other components of the system, or the entire system. It is sometimes desired to provide a clock signal having a faster frequency to a portion of the system than that of a given clock source available in the system. For example, it may be desired to double the clock signal generated by a given clock source. In order to increase internal operating speed, circuit designers sometimes use clock frequency doublers, or clock doublers.
Clock doublers also are widely employed in integrated circuit, or chip, designs to increase the frequency of an off-chip reference clock signal for internal use within the integrated circuit, such as in application specific integrated circuits (ASIC) and in microprocessor designs.